Unit 8: Cell viability by MTT assay - Practice Quiz

1 What does the abbreviation MTT stand for in the MTT assay?

2 The MTT assay is primarily used to measure which cellular property?

3 In the MTT assay, the yellow MTT is converted into a product of what colour?

4 The coloured product formed by the reduction of MTT is called:

5 Which cellular enzymes are mainly responsible for reducing MTT to formazan?

6 Which cells are able to reduce MTT into formazan?

7 The MTT assay result is typically measured using which instrument?

8 Formazan crystals are insoluble in water and must be dissolved using a:

9 In the MTT assay, higher absorbance (optical density) generally indicates:

10 The MTT assay is most commonly performed in which type of labware?

11 The MTT assay is widely used to assess the effect of drugs on cells, a study known as:

12 The formazan produced in the MTT assay is best described as:

13 Absorbance of dissolved formazan is commonly measured at a wavelength of about:

14 The MTT reaction is based on which type of chemical process?

15 In a cytotoxicity study, a control well with untreated healthy cells is used to represent:

16 Percentage cell viability from an MTT assay is usually calculated as:

17 A dead or non-viable cell in an MTT assay will:

18 The MTT assay is an example of which category of assay?

19 The stock MTT reagent solution is generally prepared in:

20 Which of the following is a key advantage of the MTT assay?

21 In the MTT assay, the yellow tetrazolium salt is reduced to formazan primarily by which cellular component?

22 What is the visible color change that indicates viable cells in the MTT assay?

23 Why must a solubilization agent such as DMSO or acidified isopropanol be added before reading MTT plates?

24 At approximately which wavelength is the dissolved formazan product typically measured in the MTT assay?

25 A treated well shows an absorbance of 0.30 while the untreated control shows 0.60. What is the percentage cell viability?

26 The value determined from an MTT dose–response curve represents the concentration of a drug that:

27 Why does the MTT assay produce a signal that is proportional to viable rather than dead cells?

28 Which control is essential to correct for background absorbance from MTT and medium without cells?

29 A researcher observes unexpectedly high absorbance in all wells including blanks. Which factor is the most likely cause?

30 Why are cells usually seeded at an optimized density before performing the MTT assay?

31 In a cytotoxicity experiment, increasing drug concentration lowers MTT absorbance. This trend indicates that the drug is:

32 Which statement best explains a key limitation of the MTT assay?

33 Test wells give absorbances of 0.45, 0.55, and 0.50; the control mean is 1.00. What is the mean percentage viability of the test?

34 Why is the MTT assay usually performed in the dark or with limited light exposure after adding the reagent?

35 A negative (untreated) control in an MTT assay typically represents:

36 Which incubation step directly determines the amount of formazan produced in the MTT assay?

37 If a test compound is intensely colored and absorbs near 570 nm, what precaution improves MTT assay accuracy?

38 Replicate wells are used for each condition in the MTT assay mainly to:

39 Compared with dye-exclusion methods like trypan blue, an advantage of the MTT assay is that it:

40 During analysis, subtracting the blank absorbance from each well's reading is done in order to:

41 In the MTT assay, the yellow tetrazolium salt is reduced to purple formazan primarily by which cellular process?

42 A researcher observes that a compound increases MTT signal at low concentrations but the cells show no increase in number under the microscope. What is the most likely explanation?

43 In an MTT assay, the mean absorbance of untreated control wells is and treated wells is . What is the percent viability of treated cells relative to control?

44 Which experimental artifact would most likely cause a falsely LOW MTT absorbance despite high cell viability?

45 Why is a reference wavelength (typically – nm) subtracted from the primary nm reading in MTT assays?

46 A test drug is a strong reducing agent (e.g., high ascorbate). What effect will this most likely have on MTT results and how should it be controlled?

47 For determining an from an MTT dose-response curve, why is data usually plotted against of concentration rather than linear concentration?

48 Which condition would most compromise the linear relationship between MTT absorbance and viable cell number?

49 The MTT assay may overestimate cytotoxic potency of a compound that induces cytostasis. Why?

50 Phenol red in culture medium can interfere with MTT readings. What is the best mitigation?

51 In a -well MTT assay, edge wells consistently show deviant absorbance. What is the primary cause?

52 Standard curve wells (cell number vs. ) fit where is cell count. A treated well reads . Estimated viable cell number is closest to:

53 Why can the MTT assay give misleading results with primary macrophages or highly metabolic quiescent cells?

54 Which statement best distinguishes MTT from MTS/XTT tetrazolium assays?

55 An MTT incubation time of hours is standard. Extending it to hours would most likely:

56 In percent-viability calculation, why must the blank (medium + MTT, no cells) absorbance be subtracted from both control and treated wells before ratio calculation?

57 Nanoparticles under test are found to adsorb MTT and formazan. What is the correct interpretive caution?

58 Two labs report different values for the same drug on the same cell line using MTT. Which variable most plausibly explains this discrepancy?

59 Why does the MTT assay not distinguish between apoptotic and necrotic cell death?

60 A high coefficient of variation (CV) among replicate MTT wells is observed. Which corrective action addresses the most common root cause?